High temperatures have led authorities to place 20 states under heat warnings or advisories, while humidity is making it feel as hot as 115 across the South and Midwest, a precursor to soaring temperatures in the East.

"The large area of high pressure responsible for the heat will expand eastward by midweek, with temperatures reaching the mid-90s in the Mid-Atlantic states as early as Wednesday," the National Weather Service reported. "Further out, this dome of high pressure is forecast to dominate most of the eastern and central U.S."

The heat index easily surpassed 100 degrees in many places: 126 in Newton, Iowa; 120 in Mitchell, S.D.; and 119 in Madison, Minn., according to the Associated Press.

And there is no relief from the relentless heat on the horizon, as 40 of 50 states will have temps above 90 this week. Temperatures are expected to near 100 from New York City to Washington, D.C.

The potentially deadly heat wave spreading across the middle of the country, with asphalt sizzling to 150 degrees, has made working outdoors brutal. In areas of the Midwest, people are chugging water while suffering from dizziness, nausea and fatigue.

It was so bad in Minneapolis that two lanes on I-94 seemed to pop right out of the highway, while at a Twins baseball game a woman suffered from heat exhaustion.

Across the state it will feel like 118 degrees, when the average temperature for this time in July is in the mid-80s.

In Phoenix, a towering dust storm has covered the city, reaching 3,000 feet in height and creating winds of 25 to 30 mph, with gusts of up to 40 mph, according to National Weather Service meteorologist Austin Jamison.

While Texas' Lake Travis is losing two inches of water every day -- it is now six feet below normal levels and dropping fast, while the water is drying up across the state.

Researchers from Texas A&M University determined that from February to June this year, the state only averaged 4.26 inches of rain, and the heat is beginning to take its toll on the local wildlife. The last time the state saw a season this dry was in 1917, when it averaged 6.45 inches of rainfall.

Much of the heat is centered over areas that are still recovering from devastating flooding this spring. The water is evaporating, adding humidity to the already oppressive temperatures.

The heat is taking a particular toll on poor and homeless people across the region. In Minneapolis, the Salvation Army's Harbor Light Center is welcoming all of those seeking refuge in air conditioning or a cool glass of water. The center's executive director, Bill Miller, said the extreme heat is far too dangerous to be turning people away.

"We don't have them leave when it's this hot. It's hot enough to get dehydrated, especially if you're drinking. In this heat, it could kill you," Miller told the Associated Press.

Betty Jean Horlacher-Bainbridge-Roswell, 55, told the AP that she stayed at the center after almost succumbing to the heat, only six blocks away.

"I almost passed out because of the heat," she said, adding that if the center had not been open, "I would have probably died."

In East St. Louis, Ill., one of the nation's poorest cities, 79-year-old Bernice Sykes spent Monday in a soup kitchen also doubling as a cooling center. Sykes, who lives on Social Security for income, had little ways to find relief from the heat -- she has no air conditioning in her tiny, $500-a-month apartment -- and one of her two tiny fans failed.

"I want to get out of there as quick as I can," she said on Monday. "Right here, I feel good. But I've got to use that one fan when I get home. It's just so hot."

Some cities are making a point to visit people who may be in need during the heat wave. Authorities in Chicago are taking special precautions after a 1995 heat wave killed more than 700 people in less than a week. Temperatures that boil over 90 degrees now trigger an emergency plan that includes visits to the frail and elderly, who are especially vulnerable. Officials are also offering rides to one of the city's six cooling centers.

As with any heat wave, electricity usage has spiked as homes and businesses have turned up their air conditioners. In Ames, Iowa, the service providers asked residents to cut back because of high demand. They asked that people turn off unused devices, close drapes during the day and wash clothes early in the morning or later in the evening to avoid peak usage hours.

Some utility companies are suggesting that customers use fans instead of air conditioners to save energy and money. In some places, however, the heat has been so intense that even the most powerful fans aren't cutting it.

"When it's 95 degrees out, and the fans blow hot air that's not enough to drive down body heat," Dr. Bobby Mukkamala said Monday to the Associated Press.